1218 THE VOYAGE OF H.M.S. CHALLENGER. 



4'. Ccdlimitra elisahethce, n. sp. (PL 63, fig. 6). 



Cephalis nearly hemispherical, with irregular, square pores, and a strong prismatic horn thrice 

 the length. Length of the two joints = 2: 7, breadth = 2:9. Thorax in the upjier third with 

 irregular network, in the lower two-thirds with parallel transverse bars, which are crossed by two 

 convergent systems of parallel beams ; in each of its three sides descend three convergent pairs of 

 stronger, parallel, curved ribs ; the two ribs of the uppermost pair are united and confluent in a 

 single odd rib in tlie lower half of tlie thorax. Each of the three vertical wings with seven 

 stronger ribs, three arising from the cephalis and the horn, four from each foot. Dedicated to my 

 dear elder daughter Elizabeth Haeckel. 



Dimensions. — Cephalis 0'04 long, 0'05 broad; thorax 015 long, 0'2 broad. 



Habitat. — Central Pacific, Station 272, depth 2600 fathoms. 



5. Callimitra emmce, n. sp. (PL 63, figs. 3, 4). 



Cephalis campanulate, with irregular, polygonal pores, and very thin bars (of the same* shape 

 as in the thorax) and with a thin bristle-shaped horn twice the length. Length of the three 

 joints = 3:6, breadth = 2:9. Thorax in its whole extent with an arachnoidal network, similar to that 

 in the cephalis and the three wings, composed of very numerous parallel threads, which are crossed 

 by two crossed diagonal systems of parallel threads. In each of the three sides of the thorax 

 descend five convergent pairs of stronger ribs, the three upper of which are crossed and form 

 large rhomboidal meshes. Each of the three vertical wings with ten stronger ribs, four arising 

 from the cephalis and each horn, six from each foot. Dedicated to my dear younger daughter 

 Emma Haeckel. 



Dimcnsio7is. — Cephalis 0-07 long, 0'06 broad ; thorax 015 long, 0'22 broad. 



HaUtat.^Central Pacific, Station 274, depth 2750 fathoms. 



Geuus 544. Clathromitra,^ Haeckel, 1881, Prodromus, p. 432. 



Definition. — S e t h o p i 1 i d a (vel Dicyrtida triradiata aperta) with three vertical 

 latticed wings, which stretch between the three divergent lateral ribs of the thorax and 

 the vertical horn of the cephalis. The front of the latter is armed with a large frontal 

 horn. 



The genus Clathromitra differs from the preceding similar Callimitra in the develop- 

 ment of a free frontal or sternal horn, a prolongation of an internal obliquely ascending 

 rod, opposite to the caudal foot. Therefore the shell in this genus possesses five divergent 

 free spines, two cephalic horns, and three thoracic feet. The lattice-work of the three 

 vertical wings is not so delicate as in Callimitra. 



^ Ctei/iromi(ra = Lattice-turban ; xTtijS^a., fiir^ct, 



