34 Moll. 
MOLLUSCA. 
CEPHALOPODA. 
The cartilages of the head of the Cephalopods are very quickly digested 
by tripsine, and differ therefore chemically from those of the Vertebrates; 
the Cephalopods are the only Evertebrates in the muscles of which inosite 
has been found. Krukenberg, Zool. Anz. iv. pp. 65 & 66. 
The ink-bag, its structure and vessels examined, in Sepia, Loligo, 
Sepiola, and Octopus, by P. Girod, C. R. xcii. pp. 364-367, 996-968, & 
1241-1243, xciii. pp. 96-99 ; abstract in J. Micr. Soc. (2) i. pp. 227, 228, 
586, 587, & 876. 
The chemical composition of the ink of the Cephalopoda has been 
examined by P. Girod, who found 60 per cent, water, 8 of mineral sub- 
stances, and 30 of insoluble organic substances, including a homogeneous 
black powder with a greenish metallic lustre, which is bleached by chlo- 
ride of lime and chlorinated water. 0. R. xciii. pp. 96-99 ; abstract, J. R. 
Micr. Soc. (2) i. p. 877. 
C. Keller has observed that Eledone assumes the colour of surround- 
ing objects, for example the yellow colour of the rock on which it was 
lying; Yiert. Ges. Zurich, xxvi. pp. 100-102. 
The only oviduct in Rossia and Spirula is on the right side ; Steen- 
STRUP, Overs. Dan. Selsk. 1881, p. 24, footnote. 
Regeneration of a part of the arm, and even of several entire arms in 
Loligo pealii (Les.) and Ommastrephes illecehrosus (Les.) stated by A. E. 
Verrill, Tr. Conn. Ac. v. p. 318 ; abstract in Am. J. Sci. (3) xxi. 
pp. 333 & 336, also Ann. N. H. (5) vii. pp. 489 & 490. Two instances of 
the reproduction of arms in Octopus vulgaris (Lam.) by S. RicciiiAitDi, 
Atti Soc. Tosc. 1881, pp. 248 & 249, and Zool. Anz. iv. p. 406. 
Several errors of Gray, Jeffreys, Verrill, Brock, and others as to the 
systematic arrangement and description of Cephalopods are pointed out 
by Steenstrup, Overs. Dans. Selsk. 1881, pp. 8, 12, 19, 22 & 23. Brock 
answers ; Zool. Anz. iv. pp. 453-455. 
DIBEANCEIATA. 
OCTOPQDA. 
Octopus vulgaris. Observations on living specimens by F. Richters, 
Das Aquarium des zoologischen Gartens in Fraukfurt-a-M. 1881. 
Octopus hairdi (Verr.), cast coast of the United States, 32-41° N. lat., 
178-524 fath., and lentus (Verr.), 33^ & 34° N. lat., 464 & 603 fath. ; 
Verrill, Bull. Mus. C. Z. viii. pp. 107 & 108, pi. ii. fig. 4, and pi. iv. figs. 1 
& 2. Hectocotylized portion of the third right arm very distinct. 
Eledone verrucosa, sp. n., id. 1. c. p. 105, pis. v. & vi., east coast of United 
States, 39-41° N. lat., 466 & 810 fath. 
Tritaxeopus, g. n. Brachial acetabula in three recognizable series. T. 
cornutus, sp. n., Owen, Tr. Z. S. xi. p. 131, pi. xxiii., Australia. 
Alloposus, g. n. Mantle united firmly to the head by a ventral and 
two lateral muscular commissures, the former placed at the base of the 
