Yes. The souls of animals seminally generated are produced by the seminal power because otherwise they would not cease to exist when the body perishes.
Animalium quae generantur ex semine, animae producuntur ex virtute quae est in semine quia alioquin non enim corrumperetur, corrupto corpore.
Since the generator is like the generated, it follows of necessity that both the sensitive soul, and all other like forms are naturally brought into existence by certain corporeal agents that reduce the matter from potentiality to act, through some corporeal power of which they are possessed.
Et quia generans est simile generato, necesse est quod naturaliter tam anima sensitiva, quam aliae huiusmodi formae, producantur in esse ab aliquibus corporalibus agentibus transmutantibus materiam de potentia in actum, per aliquam virtutem corpoream quae est in eis.
The sensitive soul is not a perfect self-subsistent substance. We have said enough (Q25 A3) on this point, nor need we repeat it here.
Anima sensitiva non est substantia perfecta per se subsistens. Et de hoc supra dictum est, nec oportet hic iterare.
Some have held that the sensitive souls of animals are created by God (Q65 A4). This opinion would hold if the sensitive soul were subsistent, having being and operation of itself. For thus, as having being and operation of itself, to be made would needs be proper to it. And since a simple and subsistent thing cannot be made except by creation, it would follow that the sensitive soul would arrive at existence by creation.
Quidam posuerunt animas sensitivas animalium a Deo creari. Quae quidem positio conveniens esset, si anima sensitiva esset res subsistens, habens per se esse et operationem. Sic enim, sicut per se haberet esse et operationem, ita per se deberetur ei fieri. Et cum res simplex et subsistens non possit fieri nisi per creationem, sequeretur quod anima sensitiva procederet in esse per creationem.
But this principle is false--namely, that being and operation are proper to the sensitive soul, as has been made clear above (Q75 A3): for it would not cease to exist when the body perishes. Since, therefore, it is not a subsistent form, its relation to existence is that of the corporeal forms, to which existence does not belong as proper to them, but which are said to exist forasmuch as the subsistent composites exist through them.
Sed ista radix est falsa, scilicet quod anima sensitiva per se habeat esse et operationem, ut ex superioribus patet, non enim corrumperetur, corrupto corpore. Et ideo, cum non sit forma subsistens, habet se in essendo ad modum aliarum formarum corporalium, quibus per se non debetur esse, sed esse dicuntur inquantum composita subsistentia per eas sunt.
The generating power begets not only by its own virtue but by that of the whole soul, of which it is a power. Therefore the generating power of a plant generates a plant, and that of an animal begets an animal.
Virtus generativa non generat solum in virtute propria, sed in virtute totius animae, cuius est potentia. Et ideo virtus generativa plantae generat plantam, virtus vero generativa animalis generat animal.
The semen of the animal or plant derives a certain active force from the soul of the generator, just as the instrument derives a certain motive power from the principal agent.
Ex anima generantis derivatur quaedam virtus activa ad ipsum semen animalis vel plantae, sicut et a principali agente derivatur quaedam vis motiva ad instrumentum.
This active force which is in the semen, and which is derived from the soul of the generator, is, as it were, a certain movement of this soul itself; nor is it the soul or a part of the soul, save virtually: thus the form of a bed is not in the saw or the axe, but a certain movement towards that form. Consequently there is no need for this active force to have an actual organ.
Illa vis activa quae est in semine, ex anima generantis derivata, est quasi quaedam motio ipsius animae generantis; nec est anima, aut pars animae, nisi in virtute: sicut in serra vel securi non est forma lecti, sed motio quaedam ad talem formam. Et ideo non oportet quod ista vis activa habeat aliquod organum in actu.