zoOLoar and botany, microscopy, etc. 201 



Another problem is offered by tbe multiplicatiou of tbe eyes in the 

 Pectinidte. Patten's explanation is altogether rejected, and a kind of 

 mosaic theory is suggested. The aberrant structure is due to the special 

 conditions of life of these Lamellibranchs, for the only free surface on 

 which eyes can be developed is the edge of the mantle, 



Nervous Elements of Adductor Muscles of Lamellibranchs.* — 

 Signer E. Galeazzi has investigated the nervous element of the adductor 

 muscles of Mytilus edulis and of Ostrea. He finds that these muscles 

 are very rich in nerve-fibres and ganglion-cells. The former give rise 

 to a very fine reticulum in the muscle ; the terminal nerve-fibrils are 

 united to the nucleus of the fibre-cell, or rather with its protoplasmic 

 nuclear prolongations. He is of opinion that all the muscular fibres may 

 have a nerve-fibre, and he cannot agree with those who think that it is 

 absolutely impossible for every muscular fibre to have a nerve. The 

 large number of ganglionic cells in the connective tissue between the 

 muscular bundles leads us to admit the presence of certain automatic 

 nervous centres in the muscle itself; the presence of these would 

 explain the considerable power possessed by the adductor muscles. 



Swelling of Foot of Solenpellucidus-t — Herr K. Mobius states that 

 if young (1-2 cm. long) examples of Solen pellucidus be magnified from 

 twenty to thirty times they may be seen to suddenly protrude their foot 

 and to swell it out. "While this is being done fluid may be seen to pass 

 from the basal parts to the free end, and this can be nothing but blood 

 which comes from the pallial reservoirs. 



MoUuscoida. 

 j3. Bryozoa. 



Stalked Bryozoon.| — Mr. J. Walter Fewkes gives the name of 

 Ascorhiza occidentalis to a new Bryozoon found at Sauta Barbara. It is 

 remarkable for having the zoarium massed into a spherical or oval 

 capitulum, which is mounted on a jointed stem ; the latter is flexible 

 and highly sensitive to the touch. It is about an inch in height, and is 

 of a uniform brownish red, the colour closely approximating to that of 

 the giant kelp (Macrocystis), with which it was found associating. It 

 has a carnose body which recalls that of Alcyonidium ; it differs from the 

 entoproetous genera in its colonial form, though its stem closely 

 resembles that of Urnatella, with which it is probably homologous. It 

 also has some likeness to Busk's genus Ascopodaria, in which there is a 

 barrel-shaped body at the base of the peduncle. The structure of this 

 form is possibly to be explained by regarding it as a Ctenostomatous 

 form allied to Alcyonidium, but with a stem. If this be so, the new 

 genus presents characters of both the great divisions of the Byozoa, but 

 a new family will have to be formed for it. Sufficient knowledge of the 

 polypide has not yet been obtained for us to say whether it is cteno- 

 stomatous or cheilostomatous. 



* Arch. Iti>L Biol. x. (1888) pp. 388-93 (1 pi.). 



t SB. Gesell. Naturf. Freunde, 1888, p. 34. 



X Anu. and Mug. Nat. Hist., iii. (ISSit) pp. 1-6 (1 pi.). 



1889. 



