72 PROCEEDINGS OF SOCIETIES. 



from whence he had found a single dead shell or skeleton — 

 enough, however, to establish its occurrence. 



Although without the experience justifying him to speak at all 

 definitely on Rotatoria, Mr. Archer ventured to bring forward as 

 new a very handsome free-swimming form belonging to the Family 

 Brachionoea, and seemingly appertaining to Perty's genus Poly- 

 chaetus, a genus disallowed by Leydig, as he imagined Perty's 

 Polychcetus suhquadratus to represent some Crustacean. Yet the 

 present form (obtained both from Carrig and Gallery districts) 

 seemed to fit here, and it at least was assuredly a rotatorian. 

 However, the character of the genus (if this animal be correctly 

 referred as congeneric with Perty's) must be slightly modified, 

 inasmuch as the present form had a carapace toothed not only at 

 the four corners of its subquadrate outline, but was minutely 

 toothed all round the margin — more strongly, however,. at the 

 upper outer angles, and more strongly still at the posterior angles, 

 which were each terminated by a long conspicuous spine accom- 

 panied by two intermediate. Instead of from ten to twelve long 

 spines on the flat surface, as in P. suhquadratus, there were four 

 only, and these of considerable length. When the animal turned 

 so as to present a side view, these spines stood forth, long and 

 conspicuous, as sword-like weapons. At a distance from each 

 lateral margin of about one-fourth of the width of the carapace, 

 and seemingly on both surfaces, there was presented a line or series 

 of spines, similar to those fringing the margin and running parallel 

 thereto and taking a nearly similar curve, from the anterior to the 

 posterior end of the carapace. All the intervening portion of the 

 surface of the carapace was thickly covered with very minute tooth- 

 like acute spines, rather irregularly scattered, and giving it a rough 

 appearance. On the " tail" (of two joints) were also two rather loug 

 acute spines, and there were two spinous " toes." The eye was 

 single, large and red, and the head lohiskered on each side by a 

 row of minute, very acute spines, very prominent when the animal's 

 head and neck became fully protruded from the carapace — in 

 fact then standing out like a comb on each side — the teeth at the 

 middle being the longest, and gradually diminishing above and 

 below. There was a frontal continuous tuft of cilia, not conveying 

 the idea of a " rotatory " motion, but waved with considerable 

 energy. The motion of this pretty creature was not very rapid or 

 active ; it seemed rather to glide, or in a measure gently flutter 

 about. The thickness of the body was comparatively pretty 

 considerable, and the viscera appeared very opaque. It would 

 seem, hence, difiicult to portray the internal organisation, and 

 Mr. Archer had much to regret that, partly from this cause and 

 partly from his want of experience in these animals, he was unable 

 to throw any light on the internal characters. In the meantime, 

 however, he ventured to think there could be no doubt but that 

 this was an undescribed rotatorian, and he would suggest for this 

 elegant creature the name of Polychcetus spinulosus. 



