H A H LUV 1 C K E'S S C I E K CE-G O S S 1 P. 



]99 



but I think it probable a closely allied si)ecies, 

 L. Hillii, often occurs, without being recognized as 

 distinct. Both these species have the same habitat, 

 being found, sometimes associated, attached to 

 floating objects, ships' bottoms, &c., and have a 

 very wide geographical range. The beautiful 

 cluster of Lepas anatifera, hg. 121, was found 



Fig. 122. Conchnderma Fia^. 123. Conrhadfrma virgata, 

 aurita, nat. size (Darwin). x 2 (Darwin). 



attached to a piece of drift timber on the Cromer 

 coast. The ConcJioderma, of which we have two 

 species, C. aurita (fig. 122) and C. virgata (fig. 123). 



Fig-. 124. Scalpelhim vulgare, x 3 (Darwin). 



are found all over 'the world attached to ships' 

 bottoms, whales, &c., and are very common ; 



certainly they are queer-looking objects. A member 

 of another genus, ScalpeUnin vulgare (fig. 12-1), is 

 found attached to corallines upon the British coast 

 in water from 20 to 50 fathoms deep, also in 

 Norway, France, and at Naples : it is a very remark- 

 able one. The Cirripedia generally are bi-sexual, but 

 there are four genera, of which Scalpelhim forms 

 one, remarkable for the sexes being either sepa- 

 rate or the hermaphrodite aided by complemental 

 males. The male, or complemental male, is para- 

 sitic upon the female, attached to different parts 

 in different species. Mr. Darwin, to whom this 

 interesting discovery is due, describes them as 

 very minute, rudimentary to a degree, in fact) 



Fig. 125. Baliitiiis porcafus. 



sometimes a mere bag of spermatzioa, destitute of 

 mouth and stomach, and of course short-lived, the 

 female being supplied with a fresh crop of males 

 at the proper season. Sometimes several of these 

 males are attached to the same female ; in S. 

 vulgare they are found, often several together, on 

 the margin of the scutum, or large valve immediately 

 over tlie orifice ; in S. ornatura there are two males 

 found, and the position they assume is one on the 

 under side of each scutum in cavities formed for 

 their reception. JSlr. Darwin supposes the larvae 

 crawl in at the orifice (as the males are periodically 

 replaced), scratch out the dead exuviae of the 

 former occupants, and there undergo their metamor- 

 phoses. 



The sessile Cirripedes, or " Aeorn-shells," are 

 well represented on all parts oft he coast, attached 

 to rocks, shells, &c. Balanus porcatus (fig. 125) is 

 found on the coast of the British isles, and its 

 habitat extends in a northern direction to Davis 

 Straits and Lancaster Sound. It attaches itself to 

 shells, Crustacea, and sponges : the largest British 

 specimen Mr. Darwin ever saw was I'o in. in 

 basal diameter. Fossil specimens from the glacial 

 deposits of the Isle of Bute have been obtained 

 nearly 2 in. in diameter and l'S5 in. in height. 

 Mr. Darwin remarks that specimens of this species 

 as well as those of B. crenatus and B. Hameri 

 (fig. 126), from northern localities and from the 

 glacial deposits, often exceed in dimensions those 

 of Great Britain and Ireland ; he has seen a 

 Scarborough specimen of B. Hameri l"6-in. in 

 diameter and 3 in. in height : tlie same species 



