Nr. 1] ANATOMICAL STUDIES ON ANELASMA AN D SCALPELLUM 18 



generally seem to be short, and debouch iinto the lacunes of the 

 surrounding oonnective tissues as previously mentioned. I shall in 

 the last section, dealing with the general results, retum to the 

 probable part which the cementary glands play in the life history 

 of Anelasma. 



Scalpellum Strømii M. Sårs. 



This species occurs in great numbers on the larger Hydroid 

 colonies in the Trondhjemfjord, where it must be characterised as 

 the commonest species of the pedunculate cirripeds. I have in a 

 previous paper (1912) described the development of its calcareous 

 plates, giving the general features of its occurence in the fjord. - 

 Scalpellum Strømii is highly organised, and feeds especially upon 

 smaller crustaceans; this is easily demonstrated by the microtomic 

 sections, and I have never situdied a fullgrown specimen without 

 finding remains of small crustaceans in the digestive intestine. 



Textfig. III. Sagittal section of the alimentar3' canal of Scalpellum 

 Strømii [X 20] m. = mouth opening; oe. = oesophagus; s. = stomach; 

 i. g. = digestive gland [\ying below the plane of the rest of the figure); 

 i. = digestive intestine; p. = proctodæum; a. = anus. 



The general features of the anatomy are as follows. The peduncle 

 in its upper part contains the ovaries, and beside these, at their 

 upper (hinder) side one pair of compound cementary glands. The 

 cementary glands never enter into the niantle. — In the thorax, the 

 oral part is not very prominent; on the other hand, it is armed 

 with highly developed, power.ful mouth feet. The mouth opening 

 leads into a rather long oesophagus (textfig. III) which almost 

 occupies one third of the entire alimentary canal. The stomach 

 is small and very little distinct; through a rather abrupt widening 

 it opens into the digestive intestine, which has a wide lumen, and 

 is almost perpendicular to the oesophagus. The prootodæum is 

 very short, and narrow, and marked off from the digestive intestine 

 by an abrupt narrowing. Just behind the transition from the 

 stomach, one pair of digestive glands opens into the digestive 



