112 Memoirs of the Indian Museum. [Voi,. II, 



Pedunculate (except perhaps Lepas anserifera) in the shallow parts of the Indian seas, 

 and hundreds of specimens have passed through my hands ; there are certainly at least 

 1,000 in the Museum collection. Curiously enough, the one character I find constant 

 has caused confusion as regards the species, viz., the separation of the carina into two 

 parts by a transverse fissure near the base. Neither Gray nor Darwin recorded this 

 character, which is by no means clear in shrunken specimens ; but Aurivillius noted it 

 in specimens from the China Sea as well as from the Malay Archipelago. Dr. W. T. 

 Caiman of the British Museum has kindly sent me the following note : — "All our speci- 

 mens labelled Dichelaspis warwickii have the carina divided horizontally as in the 

 specimens of D. equina which you send. They are unfortunately far from numerous 

 and they do not appear to include Gray's types (unless these are among some old 

 specimens of which the localities have been lost), but they do include one tablet with 

 half a dozen dry specimens labelled D. warwickii, var. in Darwin's handwriting." 

 The transverse fission of the carina is a varietal character in Dichelaspis geryonophila , 

 and it is of course possible that a race or variety of D. warwickii may occur in which 

 it is absent. If this be so, this race or variety would be the typical form, while the 

 common Indian form would become " subsp.' ' or '' var equina." 



Dichelaspis geryonophila (Pilsbry). 



Octolasmis geryonophila, Pilsbry, Bull. U. S. Nat. Museum, No. 60, p. 94, figs. 

 32a, b (1907). 



Capitulum ovoid or triangular, variable in relative transverse diameter, laterally 

 compressed, bearing five widely separated valves and usually marked on the surface 

 with fine serrated ridges representing more or less completely the five primitive valves 

 and their lines of growth. Membrane more or less opaque, colourless or tinged with 

 orange. Carina forked at the base, the length of the basal branches being variable ; 

 the vertical branch moderately broad, often of irregular outline, reaching above the 

 level of the base of the tergum ; dorsal surface with a rounded ridge on the lower part, 

 inner surface with a deep pit near the base. Tergum small, irregularly saddle-shaped, 

 often having the outline of a bird's head with the beak pointing to the aperture. 

 Scutum consisting of two branches or segments sloping towards one another ; the lower 

 branch triangular, shorter and usually broader than the upper, which is sharply 

 pointed above and directed towards the concavity in the tergum, from which it is often 

 widely separated. 



Peduncle naked, often longer than the capitulum, broader at the base than 

 above, irregularly annulated. 



Cirri, etc.— First cirrus slender and rather short, its anterior ramus similar to 

 the posterior one but shorter by about half the length of the distal joint of the latter ; 

 the distal joint of each ramus bearing near its tip a circle of stiff, sharply pointed 

 spines and terminating in a bunch of fine hairs : all the joints densely fringed anter- 

 iorly. Other cirri widely separated from the first, rather short, slender, pointed, 

 densely fringed. Anal appendages not quite reaching the junction of the two branches 



