GENUS COLE PS. 507 



the subject of remark by numerous observers, a crushed Entomostracon, or any other 

 dead or decaying organic substance contained in the water abounding with this 

 animalcule, being surrounded and devoured with an amount of happy despatch 

 that, comparing small things with great, would scarcely disgrace a troop of jackals 

 collected around some desert carrion. It has been further remarked that the 

 contour of these animalcules becomes considerably distended after their enjoyment 

 of such a meal, a fact which of itself substantially supports the view here adopted 

 as to induration of the quadrangular areas only of the cuticle, such a distension being 

 altogether irreconcilable with a continuous and trellis-like hardening of the same 

 surface. In the examples recently examined by the author, it was noted that when 

 the animalcules were feeding or otherwise stationary, the cuticular cilia exhibit a 

 continuous irregular and altogether independent vibratory action ; the vigorous 

 natatory movements, on the contrary, appeared to be accomplished through the 

 agency of the more powerful oral cilia. It was further certified, in the course of 

 this examination, that the cortex or body-substance immediately subjacent to the 

 sculptured cuticle was independently and sparsely striate or grooved in a longitudinal 

 direction, the body in such case, regarded independently of the external layer, 

 presenting an elongate, ribbed, melon-like contour. 



During the process of transverse fission the animalcules of this species, as 

 shown at PI. XXVII. Fig. 4, exhibit an altogether abnormal aspect. While the two 

 extremities retain their usual corrugated appearance, the newly developed central 

 area, having a median constriction, is entirely smooth, or marked only by the deeper 

 longitudinal furrows just referred to. So also, when the two moieties become 

 entirely separated, one half of each of these remains for a considerable interval 

 smooth and transparent, the anterior and posterior halves of the same animalcule so 

 contrasting with one another as to suggest the simile of a smooth acorn projecting 

 from its rugose cup. 



Quite recently, May 1880, the author has obtained in abundance, from a 

 pond near Acton, in company withj:he Flagellate types Trepomonas agilis and Tra- 

 chelomonas volvocina, a variety of this form or a most closely allied species, in which 

 no cusps whatever were developed at the posterior extremity, the size, quad- 

 rangular corrugation, and deeper longitudinal lines or furrows being, in' common 

 with all other essential structural details, identical with what obtains in C. hirtus. 

 At the same time the consistence of the cortical layer seemed to be thinner and 

 more transparent than usually obtains in that species, permitting a clearer view 

 of the internal contents, which were chiefly coloured green through the ingestion of 

 food-matter. While the comparative length and breadth in the examples examined 

 averaged in most instances the proportions of two to one, much shorter and almost 

 subspheroidal specimens were not unfrequently encountered. This well-marked 

 variety should perhaps be properly referred to the genus Plagiopogon, next described. 



Coleps uncinatus, C. & L. PL. XXVII. FIG. 6. 



Body ovate, slightly flattened ventrally, two and a half times as long as 

 broad ; the anterior margin bearing two recurved uncini on the more 

 flattened ventral side, four acuminate cusps developed at the posterior ex- 

 tremity. Contractile vesicle single, posteriorly situated ; endoplast discoidal, 

 central. Length of body 1-380". HAB. Fresh water. 



Coleps fusus, C. & L. PL. XXVII. FIG. 5. 



Body fusiform, subcylindrical, nearly four times as long as broad; the 

 anterior margin truncate, denticulate, attenuate and pointed posteriorly ; no 

 posterior cusps. Length 1-300". HAB. Salt water. 



D 2 



