434 ON ILTOPSYLLUS CORIACEUS AXD OTHER CR17STACEA 



Mandible stout and well-developed (fig. 3), with a large 3 (or 4) 

 lobed palp : swimming feet having both branches three-jointed 

 (figs. 4, 5), laminae of the fifth pair of feet small, nearly equal 

 in length (fig. 6) and not nearly covering the much elongated 

 ovisac, which, when fully formed, extends almost to the ex- 

 tremity of the abdomen but contains only a small number of 

 very large ova; caudal segments very short, about half as long 

 as broad (fig. 7), the outermost of the terminal setse very short 

 and bulbously dilated at the base. Length "66 mm. 



Two or three specimens were taken near the old oyster- 

 hatchery at the side of the Aln. I have also specimens of this 

 species which were taken about three years ago on the muddy 

 shores of the Eiver Glen, at Carrick, Co. Donegal. 



Bactylopus longirostris? Clans, (Plate XIII., figs. 9-12). 

 ? Dactylopus longirostris. Claus. Die frei lebenden Cope- 

 poden, p. 127, Plate xvii., figs. 4-6. 

 One imperfect specimen which probably belongs to this species 

 occurred in a gathering from pools near low-water mark. The 

 female only is described by Dr. Claus : my specimen was a male, 

 but the general characters so nearly approach those of the type 

 that I do not much doubt the propriety of the reference. The 

 antenna and some of the limbs are shown in Plate XIII. 



Thalestris mysis, Claus. 

 Thalestris peltata, (Boeck). 



Taken in tide-pools among Algse. IN'either species has before 

 been noticed in our district. 



Series 3. Leptostomata,*' Series nov. 



* XcTTTCus, slender, (jTO/xa a mouth. 



Genus Ilyopsyllus, B. & E,, 1874 {z=.Ahacola, Edwards*'). 



Ilyopsyllns coriaceus, Brady and Eobertson. (Plate XL, Plate 



XII., fig. 8). 



1873. Ilyopsyllus coriaceus, B. & E., Ann. & Mag. Nat. Hist, 



Ser. 4, vol. XII., page 132. 

 PI. IX., figs. 1-6. 



,, „ Brady, Monog., Brit. Copep., 



vol. XL, p. 143, pi. LXXXIL 

 figs. 1-10. 



* Edwards, C. L. BeschreiTmiip einigor neucn Copepoden, etc., Berlin, 1891. 



