262 Mr. E. A. Smith on 
Joticeable Features of Hydroids and the corresponding 
Meduse. 
1. Comparative abundance of Thecaphora and poverty of 
Athecata, possibly owing in part to insufficient search for the 
latter. 
2. The appearance in considerable numbers of /Zybocodon 
in May and Euphysa in August. Steenstrupia may yet be 
found if searched for at sufficient depths ; I netted it in great 
numbers in Sullom Voe, Shetland, after a westerly gale had 
stirred up the bottom; the second day I obtained a few as 
the mass were settling down, and after that I got no more. 
3. The singularly interesting and beautiful budding forms 
—HTybocodon, with its heavy group of buds round the ten- 
tacle-bulb; Rathkea, budding round the short thick manu- 
brium within the subumbrella; and the graceful Codonium 
gemmiferum (August), with the buds spirally arranged round 
the long manubrium mainly outside the umbrella, That 
figured in Forbes’s Monograph is a young form evidently 
recently detached. The adult resembles in the length of the 
manubrium and other details Haeckel’s Sarsia siphonophora. 
The very occasional appearance, often entire absence for 
the season, of Stphonophora perhaps merits incidental 
mention. 
XXXIX.—Natural History Notes from H.M. Indian Marine 
Survey Steamer ‘ Investigator,’ Commander C. F, Oldham, 
Rk.N.—Series II., No. 20. Report upon some Mollusca 
dredged in the Arabian Sea during the Season 1894-5. 
By Epoar A. SMITH. 
Witu the exception of the Amussiwm andamanicum, all the 
species quoted in this paper are from comparatively shallow 
water, and consequently have not that special interest which 
is attached to deep-water forms. It is proposed to give 
figures of the new species in a subsequent communication. 
Pleurotoma marmorata, Lamarck. 
Plewrotoma marmorata, Lamk., Reeve, Conch. Icon. fig. 21; Kiener, 
Icon. Coq. Viv. pl. vi. fig. 1; Weinkautf, Conch.-Cab. ed. 2, pl, iii. 
fig. 4; Tryon, Man. Conch. vol. vi. pl. 11. figs. 16, 16a. 
Jun.=P. hastula, Reeve, op. cit. fig. 159. 
Hab. Red Sea, Indian Ocean to Polynesia; lat. 20° 37! 15" 
