15 



smaller and more numerous than in L. typiciis\ the rostral process is much longer than in 

 L. typicus, much shorter than in L. spinosus\ the postero-lateral process of the carapace is 

 about half as long as the rostral process, thus distinctly longer than in L. typicus and several 

 times shorter than in L. spinostcs. The antennal squama is considerably longer in proportion to 

 its breadth than in L. typicus, much shorter than in L. spiiiosus; the terminal spiniform process 

 is from about one-third to a little more than half as long as the breadth of the squama. The 

 number of small, spiniform teeth on the end of telson between the two large spines shows 

 variation : in a female I found 7 teeth (fig. i e), in another female and in a male only 4 teeth 

 (fig. I d). The presence of only a single pair of lateral spines (excluding the two pairs around 

 the tip) on the telson distinguishes L. mtermedius both from L. typicus and L. spinosus. 

 According to the figures given by Faxon of his L. longirostris this species must be allied to 

 L. intertnedius, but differs sharply in having six pairs of lateral spines on the telson besides 

 the two pairs around its tip. 



In the male each of the six anterior thoracic segments has a very long, a little curved 

 spiniform process in the middle line of the sternite, second to sixth segment besides a much 

 shorter median process a little in front of the long; on seventh sternite both processes are 

 nearly rudimentary. 



A feature of morphological interest may be mentioned here. In the genus Lophogaster 

 — at least in L. typicus M. Sars and L. intermedius H. J. H. — a triangular, acute tooth is 

 found at the middle of the lower lateral margin of sixth abdominal segment, and from the 

 posterior edge of this tooth an impressed line projects obliquely upwards and forwards on the 

 side of the segment and nearly meets the corresponding line from the other half on the upper 

 side ; in this way the sixth segment is divided into an anterior smaller and a posterior larger 

 portion. In the genus Gnathophmisia Will.-Suhm a somewhat similar structure is still more 

 pronounced (it is seen on many figures in Sars' "Challenger" work), and Calmax has pointed 

 out that it shows that the sixth segment in reality is formed by the fusion of the two segments 

 well separated in the Leptostraca. I adopt this interpretation which, I think, is quite correct. 



Paralophogaster n. gen. 



Description. — Carapace with the frontal plate short (PI. I, fig. id), not covering 

 the eye-stalks, its rostral process rudimentary or wanting; posteriorly the carapace does not 

 cover the dorsal part of the last thoracic segment, and its postero-lateral wings are rounded. 

 Eyes well developed. The antennulee (fig. 2d) have the peduncle proportionately long; first joint 

 is somewhat longer than broad, a little longer and broader than the third, while the second is 

 very short; inner flagellum somewhat longer than the peduncle. The antennal squama (fig. 2d) 

 shaped nearly as in many Mysidse {Pscjidovivm G. O. S., Siriella Dana), elongated, with the 

 margins almost parallel; a marginal rim is not developed, and the terminal lobe, which is 

 marked off by an articulation, projects beyond the short marginal tooth. The maxillulae (fig. 2/) 

 without palp. The maxillae (fig. 2g) have the lobe from third joint deeply bifid, and the third 

 joint itself has on the outer side a large expansion bearing the proportionately small exopod. 



