PYCNOGONIDS 263 



longer. Ovigera relatively short, larger in the male than in the female ; 

 without terminal claw, but with a few denticulate spines (rarely absent, 

 cf. A. dohrni Thomson, '84, p. 244). Legs usually rather short, and robust 

 in the female ; frequently spinous, usually more so in the male, especially 

 on the basal joints ; femoral joint very broad in female, the outer corner 

 more or less projecting in both sexes ; second tarsal joint strongly devel- 

 oped, more or less curved, and with a few strong and several weaker 

 spines on the inner margin ; terminal claw strong ; auxiliary claws usually 

 well developed. Genital openings of female on second coxal joint of 

 all 4 pairs of legs ; those of the male at the apex of prominent projections 

 on the corresponding joints of the third and fourth pairs of legs only. 



Remarks. The genus Ammothea was first established by Leach to 

 include certain forms having chelate chelifori ; later Hodge gave the 

 name Achelia to some very similar Pycnogonids, which had, however, 

 rudimentary 2-jointed chelifori; but Dohrn ('81, p. 134) and others 

 since have shown conclusively that Achelia represents merely the fully 

 developed individuals of Ammothea. Dohrn believes that the following 

 genera Phanodemus Costa, Pephredo Goodsir, Pasithoe* Goodsir, Endeis 

 Philippi, Paribaa Philippi, Platychelus Costa, and Aldnous Costa should 

 also be considered as synonyms of this genus. 



It is possible that A. longicaudata Stimpson is identical with one of the 

 species described here, and if so it is probably with A. latifrons. (See 

 ' Remarks ' under that species, p. 266.) 



I have been unable to examine the description of A. borealis given by 

 Schimkewitsch ('95) in a paper on the Pycnogonida of the White Sea, 

 in order to compare with it the forms collected in Alaska, so that there 

 remains a possibility that one of these may be the same as that described 

 by him. 2 



AMMOTHEA LATIFRONS sp. nov. 

 Plate xi, fig. 3 ; plate xvi, figs. 1-9 ; plate xvn, figs. 1-3. 



Type. $, and ? , University of California, No. 19,503, St. Paul Island, 

 Bering Sea. 



Trunk broad, especially anteriorly, each outer corner having an erect 

 conical protuberance armed with a few spines, short, tapering posteriorly 

 in a V-shape, smooth ; sutures indistinct anteriorly, obsolete posteriorly ; 

 lateral processes very closely crowded, nearly twice as broad distally, 



1 Sars ('91, p. 137) considers Pasithoe as probably distinct, and uses it as the type of 

 a family, the Pasithoidse, including with it one other genus, Colossendeis. 



2 Subsequent comparison with Schimkewitsch's description shows that A. borealis is 

 distinct from the species described in this paper. 



