1114 THE VOYAGE OF H.M.S. CHALLENGEE. 



Genus 489. Acrobotrys, Haeckel/ 1881, Prodromus, p. 440. 



Definition. — L ithobotryida with tubes on the cephalis, and with the mouth 

 of the thorax open. 



The genus Acrobotrys differs from the preceding Botryopyle in the development 

 of radial tubes, and from its probable ancestral form, Cannobotrys, in the development 

 of a thorax, the basal mouth of which remains open. According to the varying 

 number of the tubes we may distinguish the following five subgenera (corresponding to 

 those of Cannobotrys), viz., (1) Acrobotrantha (monosolenia) with a single (apical) 

 tube ; (2) Acrohotrella (disolenia) with two divergent tubes (an apical and a sternal) ; 

 (3) Acrobotrissa (trisolenia) with three sagittal tubes (an apical, a caudal, and a 

 sternal) ; (4) Acrobotromma {tetrasolenia) with four tubes, like the four tjrpical spines 

 of Cortina ; and (5) Acrobotrusa {pento.solenia) with five feet, corresponding to the 

 five typical spines of Stejjhatiium. 



1. Acrobotrys monosolenia, n. sp. 



Cephalis trilobate, with a single straight apical tube, which ascends vertically from the apex 

 of the occipital lobe, and is pointed at the distal end, with an anterior oblique aperture. Two 

 frontal lobes paired, ovate, half as long as the helmet-shaped occipital lobe. Thorax ovate, twice 

 as long as the cephalis. Pores very scarce. 



Dimensions. — Length of the shell 0"08, breadth 0'06. 



Habitat. — Mediterranean (Corfu), surface. 



2. Acrobotrys disolenia, n. sp. (PI. 96, fig. 10). 



Cephalis trilobate, with three odd ovate lobes of nearly equal size in the sagittal plane and 

 two divergent straight slender cylindrical tubes, a vertical apical tube on the occipital lobe, and a 

 horizontal nasal tube on the frontal lobe; the middle lobe between them is somewhat smaller. 

 Thorax ovate, about twice as large as the cephalis, with constricted mouth. Pores, small and 

 numerous. 



Dimensions.- — -Length of the shell 0"1, breadth 0"06. 



Habitat. — Central Pacific, Station 265 to 274, depth 2350 to 2925 fathoms. 



3. Acrobotrys aquaria, n. sp. 



Cephalis quinquelobate, with two divergent long cylindrical curved tubes. Occipital lobe 

 helmet-shaped, with an ascending apical tube; -nasal lobe conical, with a descending sternal tube; 



' ylcro6o(r2/s= Perfect grape ; axjoV, fior^v;. 



