ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
39 
from ncrve-cells and tiro peripheral strands of striated substance due to 
the matrix cells, the distinction between sensory hairs and ordinary 
bristles, have all been described by Claus, though subsequent investiga- 
tors do not seem to have been always aware of this. 
Development of Palinurus vulgaris.* — Although several naturalists 
have worked at the development of the Sea Crayfish Mr. J. T. Cunning- 
ham has not been able to find any correct figure of the larva, or any 
account of the larval stages. Till July 1891, none but solitary speci- 
mens of Phyllosomes had been taken at Plymouth, because the right 
kind of net had not been used ; with a large net made of mosquito- 
netting and used at the surface Mr. Cunningham succeeded in taking a 
large number of these larval forms. He gives a detailed description of 
the newly hatched larva of Palinurus, the largest and most developed of 
those which he obtained being 7 mm. long ; Claus, however, obtained 
some stages at Messina which appear to be stages of the young of this 
species, and the largest of these was more than 21 mm. long ; the 
smallest Palinurus , which had all the characters of the adult, observed 
by Richters was 25 mm. long, so a small gap now only remains to be 
filled up. 
Distribution of Copepoda.f — Dr. W. Giesbrecht continues his 
account of the geographical distribution of the Copepoda collected on 
the ‘ Vettor Pisani ’ expedition. 
Vermes. 
a. Annelida. 
Work done by Lobworms.} — Mr. C. Davison, in imitation of Mr. 
Darwin’s well-known investigations into the work done by earthworms, 
took the opportunity of a short stay in Holy Island, to study the work 
performed by lobworms on the surface of tidal sands. The average 
number of castings was found to be 82,423 per acre, or more than 
50,000,000 per square mile. Castings were collected and weighed, 
when the average of four estimates showed that the amount of sand 
brought up to the surface by lobworms every year is 1911 tons per acre, 
or the weight of sand brought up by lobworms is 136 times the weight 
of soil brought up by earthworms over an equal area in the s ime time. 
The estimate is certainly below rather than above the actual quantity 
which is brought up. The average thickness of the sand is 13 inches. 
New Genus of African Earthworms.§ — Mr. F. E. Beddard gives a 
detailed account of au interesting earthworm from Lagos, West Africa, 
which he calls Libyodrilus violaceus, and takes the opportunity of report- 
ing some observations on the post-embryonic development of certain 
organs. Attention has already been called to the unique disposition 
of the nephridia ; other characters are the possession of a large unpaired 
sac, which opens on segment xiii., extends through five segments, and 
lodges receptacula ovoruin ; there are two atria, with thick muscular 
walls, which open by a common median orifice ; each is furnished with 
* Journ. Mar. Biol. Ass., ii. (1891) pp. 141-50 (2 pis.). 
f Atti It. Accad. Lincei — Rend., vii. (1891) pp. 276-82. 
} Geol. Mag., viii. (1891) pp. 489-93. 
§ Quart. Journ. Slier. Sci., xxxii. (1891) pp. 539-86 (2 pis.). 
