ECHINODERMATA. 
631 
Hhaphidoclypus microtuherculaius, sp. n., A. Ag. — Kingsmills* Islands. 
Clypeaster scwtif(ynnis (Lamk.) belongs to this genus. 
CASSIDULIDyE. 
VygorTiynchm pacijicm (Ag.), from Acapulco, is a living species of this 
genus, thus far only known as fossil.” 
Spatangid^. 
Kleinia nigra, sp. n., A. Ag., from Acapulco, probably belongs to a new genus, 
which its founder would term Hhyssohrissus. ' 
Xanthohrisstm, A. Ag., g. n., differs from Meoma (Gray) in the position 
of the vertex, which is near the anterior extremity. Lateral ambulacra of 
equal size, anterior ambulacrum in a deep groove. Subanal fasciole heart- 
shaped, with lateral branches extending to the side of the anal system.” Sp. 
X. garretti (A. A%.,—Brissopsis, Ag. MS.) — Kingsmills Islands. 
HOLOTHURIDEA. 
Baur, a. Beitrage zur Naturgeschichte der Synapta digitata. 
l)rei Abhandlungen. Dresden, 1864, 4to. (pp. 52, 60, 
120, with eight plates). Reprinted from vol. xxxi* of 
K. L. C. d. Akademie. 
Norman, A. M. On British HolotliuriadcR with reference to 
new species. Rep. Brit. Assoc. Newcastle, 1863, Trans, 
of the Sections fp. 106). 
Stimpson, AV. Descriptions of new species of Marine Inverte- 
brata from Puget Sound, collected by the naturalists of the 
North-west Boundary Commission. Proc. Phil. Acad. No. 3, 
1864 (p. 159). 
Since Johann Muller, in 1852, published his singular researches 
On Synapta digitata, describing the production of testaceous 
Gasteropods within a peculiar tube attached to the intestinal 
vessel of that Echinoderm, no other naturalist had sought, by 
the method of direct observation, to solve the curious problem 
thus raised. During the autumn of 1860, and spring and sum- 
mer of 1861, Dr. Baur visited for this purpose the Bay of 
Muggia, near Trieste, the scene of Muller^s investigations in 
1851. In April 1862 Dr. Baur communicated to the Berlin 
Academy a condensed account of his observations on the deve- 
lopment of S. digitata, and the mode of attachment of its mollus- 
cigerous sac. On his return from Trieste the author busied 
himself with the anatomical study of numerous specimens of 
S. digitata, which he had brought with him, preserved in spirit. 
The results of these inquiries were, in November 1863^ for- 
warded to the Imperial German Academy for publication. • They 
now appear in extenso, together with the detailed history of Dr. 
BaUr^s previous investigations, under the form of the copiously 
illustrated monograph which we have cited above. 
