366 



LOWER IN VER TERRA TES. 



larger than the rest, which the male then charges with one of the packets of sper- 

 matozoa soon to be described. During the coitus this arm becomes detached and 



-■"-..S^^ 



-Hectocotylization in the male Argonauta: in A is shown the sac which*: 

 open, allOAVing the hectocotylized arm to extend itself. 



remains adherent to the female, wl)ich then swims away. A new arm is formed in 



the male before the return of the breeding season. 



This subject of hectocotylization has been studied by Steenstrup, a Danish nat- 

 uralist, who finds that the arm or extent of modification is 

 variable in the different genera, but in some (among which is 

 Ornmastrephes, so common on our coast) this process has not 

 been observed. We have just alluded to the 

 packets of spermatozoa. These are called 

 sperraatophores and are found variously mod- 

 ified in different invertebrates. In Loligo, one 

 of the squids which we select as a type, it con- 

 sists of a slender capsule about half an inch in 

 length, two thirds of which is occupied by the ^vq^^^^^ 

 spermatozoa, while the remainder contains a 

 complicated discharging apparatus. On con- 

 tact with the salt water the sheath ruptures 

 at one end, and forth issues the discharging 

 ajiparatus, dragging the spermatozoa after it. 



FiG.48i.-Spermatophoreof The eggs of the ceph.alopods .are usually 

 £o/iflo ,■ n, sheath; i packet enveloped in capsules, some of which contain 



of spermatozoa; c, discharg- ^ ^ ' 



ing apparatus; d, a single as manv as two hundred effsrs. This is not 



spermatozoan. " '- ~ 



the case with all, for the writer once dredged 

 the eggs of an unknown ce]ihalo])od (? Rossia) which were separate 

 and deposited free upon the ocean's bottom. They were about the 

 size of a small pea. The shape and size of the capsules vary considei-- 

 ably. Those most commonly found on the New England coasts are 

 those of Loligo pealei. They are finger-shaped and gelatinous, and so transparent 

 that the embryos can be readily seen. Usually from twenty-five to a hundred of these 



Fig. 4S2.— Egg cap- 

 sule of LoUgo. 



