200 71ie Irish Nahiralisi. September, 



Eylals bicornuta, n. sp. 



In the sculpture of its eye-plate (Plate lo, B, fig. i.), this form is allied to 

 E. gigas, Piersig ' compared with which species the eye-plate is narrower, 

 measuring -47 mm. across; the length of a single capsule is about -27 mm. 

 The two processes on the front margin are much longer and bluntly 

 pointed, separated by a wide deep indentation. These processes arise 

 from the actual front rim of the eye-plate and are not inclosed by an 

 anterior chitinous part as they are in E. gigas. The bridge connecting the 

 eye-plates is very long and highly chitinised ; a muscle attachment, 

 roughly circular in shape, projects in a rounded prominence at the middle 

 of the posterior margin ; the hinder emargination is about \ the length of 

 the eye-plate. 



The palps closely resemble those of E. infundibiilifera^ Koen,, in shape 

 measuring about 1-42 mm. in length. Inner corner of the third segment 

 moderately developed, with numerous rather long stout spines, some of 

 which are feathered. On the lower inner surface of the fourth segment 

 there is a row of eight or nine long spines, and another of about seven in 

 a corresponding position on the outer side. The capitulum (fig. 2) is 

 about I mm. in its entire length from the spine-like process on the 

 mandible to the apex of the pharynx, length of the mandible about 

 46 ni.m. The pharynx reaches well beyond the lateral processes of the 

 maxillary plate. Front processes (" Vorderer maxillarfortsatz " of Piersig) 

 distinctlj' angled near the middle of the lower margin. 



I^ocality, Lough Gill. 



Eyials extendens (Miill.)— lyough Gill; fairly typical specimen. 



Eylals sp.— Ivough Gill; a form with small eye-plates shaped rather 

 like those of E. Soari, Piersig, possibly an undeveloped form of that 

 species. 



Hydrachna conjecta, Koen.— Examples of this species, with 

 typical ribbon-shaped prolongation of the eye-plates, were secured in 

 Lough Gill. 



Hydrachna distincta, Koen.— Specimens of an Hydrachna taken in 

 the lakelets near Rosses Point seem to be identical with H. distincta 

 Koen., though the record must be given with reserve, as there are one or 

 two points of structure which need verification. The paired dorsal eye- 

 plates (fig. 4) are very similar to those of Kocnike's species, except that 

 they appear to be larger (length, -82 mm.) in our specie?, and less curved. 

 The papillae studding the skin on the anterior parts of the animal are 

 long and conical, on the back and posterior parts they are slightly longer 

 and shaped like the teeth of a saw. The only other species with which 

 it might be confused is H. conjecta Koen. but the structure of the eye- 

 plates and papillae seem to mark it off from that species. 



"• Piersig, Anmiaire du Musk Zool. Acad. Itnperiale des Sciences de St. 

 I'etersbourg, ix., 1904. 



