Among the cirripedia inhabiting the Trondhjemfjord, probably 

 the most interesting is Anelasma squalicola (Loven) Darwin. 

 The first description of the species is found in a paper on Etmop- 

 terus spina.v (Linné) by the great Norwegian naturalist, bishop 

 J. E. Gunnerus (1763). At the base of one of the dorsal fins of 

 some of his specimens of this selachian, he ob se r ved a parasite 

 which he describes and figures, so that we easily reoognise the 

 characteristic features of the species. Gunnerus correctly ack- 

 nowledges the crustacean nature of the parasite, but does not give 

 the species any name, and his description soon passed into oblivion 

 owing to the humble and little-known journal, in which his paper 

 was published. Thus it came about that Loven, who almost a 

 century later (1845) described the parasite in question anew, and 

 gave it the name Alepas squalicola, has been generally mentioned 

 as the discoverer of the species. Loven demonstrated that the 

 species is a cirriped. His description was rather cursory, and 

 Charles Darwin therefore supplemented it in his meritorious, great 

 monograph on re cent cirripedia (1851). His detail s are given partly 

 after dissection of a specimen sent him by the Danish zoologist 

 Japetus Steenstrup, partly after information in a letter from the 

 latter. The state of preservation of his specimen was, however, far 

 from satisfactory, and many anatomical questions consequently 

 remained open to later investigations. Darwin created a new genus 

 for the species, viz. Anelasma. Later on, Gruvel (1905) considers 

 Anelasma as the type of a subfamily Anelasminae, which 

 besides Anelasma also comprises the genera Gymnolepas, and 

 Chaetolepas; he gives, however, no further contributions to our 

 knowledge of the anatomy of Anelasma squalicola. 



Some new anatomical details have in the meantime been given 

 by Kossmann (1874), and later by Geoffroy Smith (1906). Darwin 

 found no transversal striation in the muscle fibres of Anelasma, 

 and judged this as a primitive feature; Kossmann, however, 

 demonstrates the transversal striation of the muscles, and thus 

 shows us that the species in this respect joins the remaining cir- 

 ripeds. He further points out that the species in many respects 

 seems to form a link between the cirripedia p e d u n c u 1 a t a 

 and parasitica. Geoffroy Smith gives some details concerning 

 the structure of the filiform offshoots of the peduncle, and of the 



