108 STALK-EYED CRUSTACEA. 
Famity ERYONTID 4. 
ERYONICUS Bare. 
Ann. Mag. Nat. Hist., 5th Ser., X. 456, 1882; Rep. Challenger Macrura, p. 122, 1888. [Zryoneicus.] 
The genus Lryonicus was established by Spence Bate for the reception of 
aremarkable Eryonid, Evyonicus cecus Bate, secured during the voyage of 
the “ Challenger,” Feb. 11, 1873, off the Canary Islands, ostensibly from a 
depth of 1620 fathoms. This specimen, which was only 13 mm. (4 in.) long, 
remained unique until 1890, when a similar specimen was captured in the 
Bay of Bengal, 690-920 fathoms, by the naturalists of H. M. 8. “ Investi- 
gator.” The latter specimen, which was larger than the one obtained by 
the “Challenger” (36 mm. long), was recorded but not described by Wood- 
Mason in the Annals and Magazine of Natural History, 6th Series, VII. 
199, 1891. Wood-Mason believed it to be an immature form of some species 
of Pentacheles ( Polycheles), as had already been suggested by Spence Bate. 
Eight specimens of Eryonicus were secured by the “ Albatross” in 1891, 
the largest of which measures 62.5 mm. (nearly 2} in.) in length. With so 
many and such large individuals at my disposal, I have been able to correct 
some of the errors and supply some of the deficiencies in Spence Bate’s 
account of this interesting animal. 
The first abdominal somite, which was destitute of appendages in the 
? 
type described by Bate, in the largest of the “ Albatross” specimens (a 
male) bears a pair of limbs specialized for sexual functions, very like the 
corresponding appendages in the genus Polycheles. The inner branch of the 
appendages of the second abdominal somite bears ¢wo processes (stylam- 
blydes), as in the other genera of Eryontide. The first abdominal somite 
of the female, also, carries a pair of less highly modified, simple, two-jointed 
appendages. The existence of well developed external sexual organs, taken 
” 
in connection with the dimensions of the largest of the ‘ Albatross”’ speci- 
mens, at once disposes of the theory that Hryoucus is an immature stage 
in the development of some other genus. 
The ophthalmopoda, far from being absent in this genus, as Bate asserts, 
present in the adult (see Plate XXX., Figs. 1, 1", 1°) the same form and 
dimensions as in the genus Polycheles. They consist of a large lobe, im- 
movably fixed in a deep sinus in the anterior border of the carapace ; this 
lobe sends forth an elongated cylindrical process outward and downward 
