KUNGL. SV. VET. AKADEMINS HANDLINGAR. BAND 63. N:0 7- 11 



he had before him, at least for the most part, specimens of the longer species or L. leio- 

 pygos ( = clypeata). His statement of 6 posterior achaetous segments is obviously taken 

 from his description of {Cl.) ebiensis in 1892 (ef. p. 10 above); fig. 1 of this paper is re- 

 produced in the »Monograph» as fig. 18 of pl. 100. Mc Intosh further writes (31, p. 

 316): »So far as can be observed the Leiochone clypeata of St. Joseph appears to be 

 this species, for ...» As already mentioned, L. clypeata is placed with hesitation, on 

 the list of synonyms, but in describing the species Mc Intosh has evidently not at all 

 hesitated to use St. Joseph' s description, for it is only from this source he can ha ve got 

 the statements as to the number of setigerous segments. With regard to the number 

 of posterior achaetous segments, on the other hand, his description of 1892 (15) has 

 prevailed. Finally he has totally omitted any comparison between his own earlier de- 

 scription of the posterior end and that of St. Joseph (ef. p. 9 above). That Mc Intosh' s 

 description of L. ebiensis must be based on specimens of L. clypeata, is also proved by the 

 fact, that his own L. clypeata (p. 320) does not represent that group of Leiochone, which 

 lacks a cephalic plate, being perhaps not even a Leiochone at all. 



It now remains to examine Mc Intosh's description of the new species Leiochone 

 johnstoni (31, p. 319). This species has no cephalic plate and the l sfc setigerous segment 

 is short. »No eyes are visible», says Mc Intosh, but in fig. 19, pl. 100, they are to be 

 seen. With exclusion of the posterior ring, the number of the achaetous posterior seg- 

 ments is stated by Mc Intosh to be 3, 1 or 5 ( ! ). On each side of the ventral anal cirrus, 

 which is the longest, there are 2—3 cirri, situated rather near the first-mentioned one. 

 The number of setigerous segments is unknown. The uncini somewhat resemble those 

 of L. leiopygos, but are obviously less drawn out in their upper, outer part. 



With regard to Mc Intosh's different statements as to the number of the posterior 

 achaetous segments, there is no reason to assume any other variation in this point than 

 in exceptional cases. If we further assume as correct, that »five segments posteriorly 

 are devoid of bristles», we find practically a complete agreement between Mc Intosh's 

 and my own description of L. johnstoni. When t hus identifying the species before me 

 with L. johnstoni, I assume partly that Mc Intosh's species has 19 setigerous segments, 

 partly that the reason why the laterally placed anal cirri in my material nowhere compose 

 more than a couple on each side, is to be found in incomplete regeneration. 



In both L. leiopygos and L. johnstoni the altered anterior capillary setae on the 

 middle segments (from about the 8 th to the 15 th setigerous segment) may be observed, 

 and it is not improbable that similar setae exist in other species of the same genus with- 

 out having so far been discovered. Cf. especially L. leiopygos. 



In any case I venture to hope that the descriptions given by me below, made from 

 a material which in most cases was exceedingly suitable for investigation, will contri- 

 bute to a definite limitation of the respective species. 



