ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 31 
anatomy, reproduction, habitat, food, and general distribution, but the 
anatomical remarks have been cut rather short. 
Structure and Relationships of the Solenoconcha.* — Dr. L. H. 
Plate begins by describing the structure of Dentalium (_D. dentale , 
D. vulgare , D. rufescens) and of Siphonopoda ( Siphodentalium vitreum, 
Siphoentalis ciffinis, Cadulus subfusiformis ), and then discusses their 
systematic position. Gastropods they resemble in the radula, the jaw- 
plate, the unpaired shell, the retractor muscles, the unpaired gonads, 
and the buccal nervous system. Among Gastropods the Rhipidoglossa 
resemble Solenoconcha in bilateral symmetry, distinct head, oesophageal 
pouches, separate sexes, and perhaps even in the disposition of the 
mantle. The Solenoconcha resemble Chitonidae in their symmetry, in 
the sub-radular organ, and in the oesophageal glands. Still more does 
the Patella type resemble that of Dentalium. With Lamellibranchs 
Solenogastres 
Mollusc 
also, as Lacaze-Duthiers has urged, the Solenoconcha present affinities, 
e.g. symmetry, nervous system, nephridia, &c. But the conclusion to 
which Plate comes is this, that the Pro- Rhipidoglossa, ancestors of the 
Rhipidoglossa, are the roots whence the Solenoconcha and the Lamelli- 
branchs have sprung. With Grobben’s idea that the Solonoconcha are 
related to Cephalopods the author entirely disagrees. His views are 
expressed in the accompanying diagram. 
Molluscoida. 
a. Tunicata. 
Budding of Botryllus.f— Mr. A. Oka has made a study of the 
process of budding in Botryllus. His results point clearly to the meso- 
dermic nature of the peribranchial sac, which arises from the gut like 
the coelom pouches in Amphioxus. He believes that the peribranchial 
space is a secondary coelom. The vascular cavity is continuous with 
* Zool. Jahrb., v. (1892) pp. 301-86 (4 pis.). See this Journal, 1892, p. 465. 
t Zeitschr. f. Wiss. Zool., liv. (1892) pp. 521-47 (3 pis.). 
