GASTEROPODES. 297 
a straight line ; the middle was irregularly circular, as if for casting a knot, 
and each end prolonged. The rope is always solid and clumsy, and 
above a line in thickness. The motion of Nautilines within the former 
spawn of July 4th, was visible on the 18th under the microscope. 
This spawn is always of the purest white ; and the multitude of ova 
such as to make it appear almost solid. It comes to maturity, and the 
Nautilines are liberated in fifteen days. 
This animal is not common. 
Prats XLII. 
Fia. 8. Doris (Goniodoris) nodosa, back. 
9. Belly. 
10. Tentaculum. 
11. Branchiz. 
12. Spawn. 
13. Spawn. 
14, Portion of spawn, enlarged. 
4. Doris (ANCULA) crIsTATA.—Plate XLII. Figs. 15, 16, 17, 18, 19, 20. 
An animal is described by Messrs Alder and Hancock under the 
name of Ancula cristata, as given by a foreign naturalist, with which I 
apprehend the following may be nearly identified. But I acknowledge 
that there is such an enormous difference in the size of the magnified 
figures in the work containing them and any specimens I have had, that 
I feel some perplexity. A musquito magnified to the size of a partridge 
ceases to resemble the original. 
Length seven lines ; breadth a line. Body thick, lanceolate. Head 
somewhat hammer-shaped, front obtuse, with an obtuse prolongation to- 
wards each side. Tentacula two, each originating from between two 
slender flexible processes about half the length of the tentaculum. Un- 
der half of the tentaculum smooth ; each side of the upper half deeply in- 
dented on each side by about ten short leaves. The tentacula somewhat 
clavate, with the tip cylindrical, and they are slightly recurved during 
progression. ‘Two minute black eyes are behind their roots. 
2P 
