184 THE SCHIZOPODA. 



GNATHOPHAUSIA Willemoes-Suhm (IS75). 



The material is scanty, consisting of seven specimens belonging to three 



well-known species. 



2. Gnathophausia ingens (noimN). 



1870. Lopliogaslcr ingens Dohrn, Zeitschr. wiss. Zool., 20, ]). 010; taf. 31, figs. 12-14. 

 1885. Gaalhophausia ingens G. O. Sars, Challensor Rci)t., 13, p. 30, pi. 2. 



Gualhophausia calcamta G. O. Sabs, Challenger Kept., 13, p. 35, pi. 4. 



1891. fhiathophausia bengalcnsis Wood-Mason, Ann. Mag. Nat. Hist., scr. G, 8, ]i. 2G9. 

 1906. (liiathophaiDiia ingens Ortmann, Proc. U. S. Nat. Mus., 31, p. 28. 



Gnathophausia calcarata Ortmann, Proc. U. S. Nat. Mus., 31, p. 30, pi. 1, figs. 2a, 2b. 



Sta. 36S1. Aug. 27, 1899. Lat. 28° 23' N., long. 126° 57' W. 350 fms. to surface. 1 specimen. 



Remarks. — The specimen, which measures about 68 mm., agrees well with 

 Ortmann's description of G. calcarata G. O. S. Dr. A. Alcock kindly sent me 

 Wood-Mason's type of G. bcngalcnais and I can confirm Ortmann's interpreta- 

 tion that it is identical with G. calcarata. Wood-Mason said that "the upper 

 lateral keels are strongly roof-shaped," Init Ortmann was unable to understand 

 the meaning of this sentence; I suppose, however, that Wood-Mason intended 

 to say that the keels in question protrude laterally as eaves above the vertical 

 sides of the carapace, when this is seen from behind or in an optic transverse 

 section. 



Ortmann (1. c, p. 28-30 and p. 34) was of the ojiinion that G. ingens 

 (Dohrn) G. O. Sars, is the full-grown female of G. calcarata (Will.-Suhm, MS.) G. 

 O. (S., and I am able to add three points corroborating his view. I examined 

 Sars's " Challenger " sj^ecimens of G. ingens (Dohrn) in the British Museum and 

 found that it possessed the two pairs of oblifiue keels on the upper surface of the 

 carapace, these keels being even well tle\'eloped and completely sitnilar to those 

 on the type of G. calcarata; Ortmann rightly su]:)posccl that these keels had been 

 overlooked by Dohrn and Sars. Furthermore Sars's figure of the ventral epi- 

 meral plates of the sixth abdominal segment in G. ingens is incorrect; the slit 

 between the two posterior lobes of the plate is longer and narrower in proportion 

 to tlie breadth of the lobes than in his fig. (PI. II), and, what is of more 

 importance, each lobe has its outer terminal angle produced into a somewhat 

 short, pointed tiji, while the inner terminal angle at the slit is acute but \eiy 

 slightly produced, thus situated somewhat in front of the outer tip and shaped 

 about as in G. calcarata, but differing notably from Sars's fig. 6 of G. ingens. 

 Finally Sars says in the diagnosis of G. ingens: " branchiostegal spines obsolete," 

 but he overlooked that these spines liad been broken ofT in his specimen. I 

 think one is now justified in adopting Ortmann's supposition and may safely 

 take the step to withdraw G. calcarata, considering it only as a synonym. 



