MUSEUM OF COMPARATIVE ZOOLOGY. 3G3 



as the peduncle of the second antennae and the telson entire, and his own 

 name Galanthis including the species with the two pairs of antenna; subequal 

 and short and the telson cleft or double. In 1861 he suppressed the name 

 Galanthis in favor of Nicolet's Nicea. The proportion of the antennae and 

 the form of the telson brought together by Bate in his generic diagnoses are 

 not in reality always concomitant, and Heller for the first time properly dis- 

 tinguished the two genera by the character of the telson alone. Grube * 

 adopts the relative length of the two pairs of antennas (at most a specific 

 character) as the generic distinction. All his species of Allorchesles have a 

 double telson, and should be transferred to Nicea. 



Boeck,f apparently misled by the fact that Bate carelessly describes Nicea 

 Nilssonii with an entire telson, and places it under Allorchesles^ would unite 

 the two genera, giving as a generic character " appendix caudalis brevis, 

 crassa et Jissa." He furthermore considers both Allorchesles and Nicea 

 synonymous with Rathke's older Hyale,§ the type of which, //. Pontica, was 

 carefully described and figured with the posterior caudal stylets two-branched. 

 Boeck has not had access to Rathke's type, as far as I can learn ; but in a 

 specimen from the Mediterranean, " which is doubtless Rathke's species," 

 he finds the last pair of saltatory appendages one-branched. This assump- 

 tion of identity, it seems to me, cannot outweigh the careful description and 

 illustration of the founder of the genus, unless confirmed by examination of 

 the type of Hycde Pontica. 



In 1874 Professor S. I. Smith described a new amphipodous genus, Hya- 

 lella, from the fresh waters of the United States, differing from " Hydle " in 

 having a styliform fifth segment to the palpus of the maxillipeds and an 

 entire telson. The so-called fifth segment may perhaps be more correctly 

 regarded as- a movable spine, like those seen both lateral and terminal on 

 the caudal stylets, or like the unguis which tips the dactylopodite of the 

 thoracic legs. However this may be, it is quite as well developed in sev- 

 eral species oi."Hyale" (Nicea), and is not therefore a generic character. 

 Hyalella is then a synonyme of Allorchesles. 



* Beitr. z. Remit, d. istrischen Amphipodenfauna, Arch. f. Natur. 1866. pp. 382, 

 387. 



t De Skandinaviske og Arktiske Amphipoder, beskrevne af Axel Boeck. Forste 

 Hefte. 1872. I am indebted to Dr. Hagen for a translation of Boeck's Norwegian. 



% Doubtless a large number of the species placed under Allorchesles by Bate in his 

 Catalogue of the Am})hipoda in the British Museum have in reality a divided telson. In 

 fact, it would seem that the telson is cleft in most of the marine forms, and such prob- 

 ably formed the bulk of Dana's original genus Allorchestes. The only types of Dana's 

 species that I can discover are two specimens of A. media in the Museum of Compara- 

 tive Zoology. In these the telson is cleft to the base. This, however, will not affect the 

 synonymy as given above. 



§ Zur Fauna der Krym, p. 87, PI. V. Figs. 20-28, 1836. 



