'32 DR. R. V. WILLEMOES-SUHM ON SOME ATLANTIC 



2. Gnathophatjsia zoea, n. sp. 



In its general appearance this species differs from On. gigas at once by the presence 

 of a long posterior spine at the dorsal shield. 



The specimens, two males and two females, were got in very different places. (1) 

 June 30, a male was obtained off the Azores in a depth of 1000 fathoms ; it has a length 

 of 49 millims., the rostrum being 18 millims. long. (2) August 25, in lat. 1° 47' N., long. 

 24° 26' W., a male came up from a depth of 1650 fathoms : length 58 millims., with a 

 rostrum of 17 millims. (3) August 26, a female from 1500 fathoms, in lat. 1° 22' N., long. 

 26° 36' W. : length 81 millims., with a rostrum of 14 millims. (4) September 12, off Rio 

 San Francisco on the coast of Brazil, another female came up from 750 fathoms : length 

 31^ (rostrum 7) millims. According to this the size of the males varies between 49 and 

 58 millims., and that of the females between 31J and 81. 



The substance of the dorsal shield is flexible, like strong parchment ; it is as in Gn. 

 gigas a duplicature of the skin, adhering to the body only in the first segments, and in 

 no connexion with the five posterior segments of the pereion. A ridge running over the 

 whole length of the shield is continued into a long triangular "rostrum, which, in the 

 males, is much longer (^ of the length of the whole animal) than in the females (-§- of the 

 length). The posterior spine is a continuation of this ridge, and has in both sexes a length 

 of 6-8 millims. Both rostrum and posterior spine are triangular and armed with small 

 secondary spines, which in the former are to be seen on all sides, in the latter only on two 

 sides. The posterior spine reaches backward to the third abdominal segment ; and all the 

 segments of the pereion are covered by the dorsal shield, with the exception of the lateral 

 parts of the last one. 



The posterior angles of the shield are rounded. In front there is a sharp spine above 

 each eye, and another somewhat smaller one below it, just inside, at the place where we see 

 the round plate, to which are attached the muscles of the oral apparatus. A transverse 

 sulcus, a transverse ridge, and two longitudinal ridges (besides the larger central one) 

 divide the shield, as in the former species, into cephalic, hepatic, cardiac, branchial, and 

 marginal regions (PL X. fig. 4). 



The inner or first antenna hardly differ from those of the preceding species. Their 

 funiculus only reaches to the middle of the squamiform appendage. The outer or second 

 antenna? differ from those in Gn. gigas by the shape of their scale, in which only one 

 spine is visible (PI. IX. fig. 2, a I), while in the larger species there are five spines. 



The parts of the mouth in this species could be dissected and submitted to micro- 

 scopical examination, which showed that they are very much like those in Lophogaster. 

 The very strong and big mandibidce (PI. IX. fig. 3) have a palpus the second joint 

 of which is somewhat recurved. The third joint shows two kinds of hairs — very short 

 ones, which also Sars has figured in his genus, and longer ones at the top. The upper 

 lip has the same cordiform shape as in the preceding species ; and the tmder lip (PI. IX. 

 fig. 4) is more clumsy than that of Lophogaster, and does not show so deep an incision, 

 but has the same small hairs at its anterior border. The first maxilla is distinguished 

 by very strong bristles in its inferior portion, and has a palpus which, among Schizopods, 

 has hitherto only been found in Nebalia (fig. 5, p) ; at the top of this palpus we find very 



