KUNGL. SV. VET. AKADEMIENS HANDLINGAR, BAND 47. N:<> I. 



-I 



of the respectivc pentagons is eounted from without fcöwards ili<' interiör. In fche 

 three or four first orders of pentagons the teeth gradually increase, fche first having 

 the smallest ones. In the following they decrease in size and p;iss imperceptibly 

 över into the seemingly more disordered armature of the oesoplnvjus. The innermosi 

 teeth are reprented by minute pointed warts (figs. 1 a, 6 a and 12 a). 



In Priapulus caudätus Lam., from northcrn and aretie regions, seven pentagon 

 are distinguishable (fig. G and fig. 1 in the text). The teeth of each pentagon are 

 of equal size. The teeth of the first pentagon are rather large, though of course 

 smaller than those of the three succeeding pentagons, and disposcd in sueh a manner 

 that one of them has its place in the ventral median line. On each side of the 

 povverful central spine, the teeth bear one or two, seldom more, lateral rather strong 

 spines, often of a somewhat irregular shape and 

 position. 1 The small teeth of the gullet are more 

 irregular in shape and provided with two lateral 

 spines on each side. 



In Priapulus caudätus forma tuberculato- 

 spinosus Baird, from the antaretie sea, six pent- 

 agons are distinguishable (fig. 1 and fig. 2 in the 

 text). The teeth of each pentagon are equal in 

 size, except the two opposite dorsal ones of the 

 fourth pentagon, these being considerably grea- 

 ter than the remaining ones. The teeth of the first 

 pentagon are minute in size and disposed like 

 those in Priapulus caudätus Lam., but their central 

 and three or four lateral spines are diminutive and 

 obtuse. On each side of the powerful central 

 spine, the teeth bear three or four lateral spines, 

 regular in shape an position. In the smaller 

 irregularly arranged teeth, inside the pentagons, the number of lateral spines in- 

 creases up to seven or eight, but decreases again towards the interiör of the gullet. 



In Priapulus bicaudatus Dan., from the aretie sea, five pentagons are distin- 

 guishable (fig. 12 and textfig. 3). The teeth of each pentagon are of equal size. The teeth 

 of the first pentagon are minute in size and divided in two, which do not form 

 the angles of the pentagon but are situated on each side of them; consequently 

 the first pentagon has ten teeth, 2 disposed in five pairs. Éach of those teeth which con- 

 stitute a pair has a somewhat triangulär shape and is provided with small obtuse protru- 

 sions,corresponding to the spines in othér teeth. On each side of the forcible central spine, 

 the teeth bear three to five lateral spines. In the smaller irregular teeth, inside the 



Fig. 1. Priapulus caudätus Lam. Diagram 

 of the dentary apparatus. D, dorsal side; V, 

 ventral side; 1 — 7, the seven pentagons of teeth. 



1 In a little specimen from Spitzbergen Wliales Point) the lateral spines on each side of the central one 

 varied from one to five. In full-grown specimens, the lateral spines of the teeth of the seven pentagons art 

 strong and range from one to two, seldom three. 



2 Koken and Danielssen have overlookcd the teeth of the first pentagon. Fauna littoralis Xorvegiie. III. 

 Bergen 1877. p. 148. 



