.">4 THE VOYAGE OF H.M.S. CHALLENGER. 



The genus Lucemaria, the oldest known form among the Stauromedusse, was founded 

 by 0. F. Muller, more than a hundred years ago, for the large and widely distributed 

 Acraspeda of the North Atlantic Ocean, which he named Lucemaria quadricomis (Prodom. 

 Zool. Dan., 1776, p. 227). This notable and well-known form alone can therefore be taken 

 as the typical species by which to define the character of the genus Lucemaria. Later 

 authors, such as Keferstein, Leuckart, Taschenberg, and others, have, for the most part, 

 placed all other later known Lucernaridae in this genus. However, for reasons given in 

 the System der Medusen (1879, pp. 380, 387), I considered the division of the true 

 Lucernaridaa into four genera justified, and therefore limit the genus Lucemaria to the 

 forms without mesogonial pouches and without marginal anchors (EleutherocarjndcB 

 inauriculata) . The genus Lucemaria is distinguished from the closely allied genus 

 Haliclystus (which is very minutely described by Clark in his monograph on Halidystus 

 awricula, 1878) by the absence of marginal anchors or marginal papillae, and from the 

 two other genera of the family (Halicyathus and Craterolophus) by the absence of the 

 peculiar " mesogonial pouches or mesenteric pouches," which in the latter penetrate from 

 the stomach into the subumbral wall of the four perradial gastral pouches. The species 

 described below (from 3240 feet deep) is the first deep-sea Lucernarid, as all the other 

 species of this family hitherto described, are littoral, or only found at moderate depths 

 (from 20 to 50 feet at most). This species is, moreover, distinguished in several ways 

 and by many peculiarities (especially by the slight development of the eight arms and 

 the complicated structure of the genitalia) from the four other hitherto known species of 

 this genus, so that it is perhaps better to constitute it the representative of a special 

 genus, Lucemosa. 



Lucemaria bathyphila, Haackel (Pis. XVI., XVII.). 



Lucemaria bathyphila, Hjeckel, 1880, System cler Medusen, p. 640, No. 597. 

 Lucemosa bathyphila, Hceckel, 1880 (in litteris). 



Umbrella bell-shaped, when extended, nearly as broad as high. Peduncle almost rudi- 

 mentary, conical, one-chambered, hardly one-sixth so long as the cavity of the umbrella, 

 with four strong, linear, interradial, longitudinal muscles. Eight arms united in pairs. 

 The four perradial arches of the umbrella margin three times as broad and deep as the 

 four interradial arches; each arm with 80 to 120 tentacles; eight genitalia, very broad, 

 separated by a broad interspace from the base of the peduncle as well as from the 

 end of the arm, each genitalium composed of numerous (above 200) separate sacs, 

 which again consist of a large number of isolated follicles. Horizontal diameter of the 

 umbrella, 50-60 mm. ; vertical diameter, 60-80 mm. 



Habitat. — The North Atlantic Ocean, between the Faroe Islands and the Shetland 

 Islands. Lat. 60° 3' N., long. 5° 51' W. Depth, 540 fathoms (John Murray). This species, 



