12 THE VOYAGE OF H.M.S. CHALLENGER. 



brought to light the fact that it is by no means the only genus of deep-sea 

 ( 'irripcdia. 



Wli.it has been added to our knowledge of the anatomy and embryology of the Cirri- 

 pedia since the publication of Darwin's book? 



The beautiful researches of Krohn 1 are no doubt the best published on the anatomy 

 f the Cirripedia since that date; they contain a detailed description of the cement- 

 apparatus of Lepas and Conchoderma, and for the first time an accurate description 

 of the female genital organs of Lepas and Balanus tintinnabulum. It is well known 

 that Darwin 8 hesitated to accept the results which Krohn arrived at with regard to the 

 opening of the oviduct into the sac at the base of the first pair of cirri. The exactness 

 of Kxohn's description was acknowledged by Kossmann, 3 after having been disputed by 

 Pao-enstecher. 4 I may add that the opening of the oviduct into Darwin's " auditory 

 i. " requires very delicate dissecting, but that once achieved, a microscopic prepara- 

 tion may be made of the sac with the oviduct attached to it. In one of my preparations 

 the oviduct, at a short distance from the sac, contains ovarian eggs. As was accu- 

 rately stated by Darwin, the sac often contains a proportionally large and laterally 

 flattened second sac, the opening of which is directed towards and attached to the 

 opening of the oviduct in the outermost sac. Of course, since the supposition of Darwin 

 as to the auditory function of the whole apparatus must be abandoned, his opinion 

 as to the nature of this sac cannot be accurate. Krohn supposes that this innermost 

 sac is furnished with a very elastic wall, which, when the sac is full of eggs, dilates 

 very considerably, and loosens itself from the attachment of the oviduct, forming in this 

 way the ovigerous lamellss. 



Kossmann, on the contrary, calls this shoe-shaped sack a " Klumpen," i.e., an 

 irregularly-shaped mass. According to him, this, if not totally solid, is only furnished 

 with very irregular cavities, which cannot be filled with eggs from the oviduct. Even if 

 one of these cavities were in direct communication with the oviduct, the con- 

 tractions of the latter could never develop the force necessary to swell out the body 

 till it formed the very tender cuticle which encloses the eggs of the Lepadids. The 

 mass does not show a trace of a cellular structure, and though very extensile, it is 

 very tough also, and offers great resistance to any tearing with needles. The mass 

 is evidently the product of an aimless secretion of the epithelium-cells of the sac 

 at the extremity of the oviduct. When the eggs pass through the oviduct these cells 



1 Krohn, A., Beobachtungen liber den Cementapparat und die weiblichen Zeugungsapparate einiger Cirripedien 

 Archiv. f. Natwgesch., Jahrg. xxv. 1859. 



2 Darwin, Ch., On the so-called "Auditory-Sac" of Cirripedes, Nat. Hist. Review, 1863. 



3 Kossmann, R., Suctoria und Lepadidae, Arbeit, zool. zoot. Instit. JViirzburg., i., 1874. 



J Pagenstecher, A., Beitrag zur Anatomie und Entwickelungsgeschichle yon Lepas pectinata, Zeitschr.f. mss. Zool, 

 Bd. xiii. 1863. 



