36 COPEPODA 



Macrocalanus G. O. Sars. 



1883. Calanus pars Brady. 



1905. Macrocalanus G. O. Sars. 



1906. Megacalauus Pearson. 

 1906. Heterocalanus Wolfenden. 



1907. Megacalanus G. O. Sars. 



1908. Megacalanus Farran. 

 1909 Bradycalanus Scott p. 14. 



1911. Heterocalanus Wolfeuden p. 201. 



Since Wolfenden, as the first, established a new genus, Magacalanus, for a big Calanoid from 

 the deep Atlantic, four other genera viz. Macrocalanus G. O. Sars, Heterocalanus Wolfenden, Bathy- 

 calanus G. O. Sars, and Bradycalanus Scott, more or less related to the original one, have been 

 established. A good deal of confusion about the right definition of these genera has risen. Scott 

 and Wolf enden have both tried, but only with partial success, to find the right names for the most 

 natural groups of species. 



About the genus Bathycalanus G. O. Sars not much discussion in necessary. By Sars it was 

 characterized by the ribbon-shaped and densely-ciliated bristles on the lobes of the maxillae and 

 maxillipeds, and by the two-segmented Re of pes I; the described species (B. Richardi} has 2 distinct 

 spines covering the rostral filaments and "assez greles" rostral processes. As Wolfenden has examined 

 a specimen of B. Richardi G. O. Sars with indication of segmentation between Re II and III pes I, 

 and as his other species B. maximus Wolf, has a three segmented Re pes I (without Se as in the 

 other species) and with long and stiff rostral processes, he regards the structure of the maxillae -|- 

 maxillipeds and the frontal teeth as the most important character (p. 198). Scott (1909 p. n) is certainly 

 wrong in not accepting Bathycalanus maximus Wolf, as belonging to Sars' genus on account of the 

 differences in the segmentation of Re pes I. 



Wolfenden writes (1911 p. 201) "Ob die Charaktere dieser drei Gattungen geniigen, um ihre 

 Abtrennung von einander zu rechtfertigen, kan Ansichtssache sein; wenn aber die generische Unter- 

 scheidung von Bathycalanus und Megacalanus anerkaimt wird, so erscheint auch die Abtrennung von 

 Heterocalanus als eigene Gattung berechtigt, derm Heterocalanus unterscheidet sich von jeder cler 

 beiden andern Gattungen deutlich durch die Bewaffung der Maxillipeden, die Form des Kopfes uud 

 den Ban des 5 Fusspaares". From this point of view Wolfenden as well as Scott (1903 p. n) are right, 

 and Sars wrong in referring his Macrocal. princeps and longicornis to the same genus, but his 

 Bathycalanus Richardi to a new genus. The genus Megacalanus Wolf, with M. princeps Wolf, as the 

 type is characterized by the hook on the anterior surface of the Basp. Ill pes I and the slender bristles 

 of the maxillae. Wolfenden, who rightly recognised that Brady's Calanus princeps is nearly 

 related if not identical with his Heterocalanus mcdius, ought in every case in his later publications to have 

 accepted Sars name Macrocalanus, which according to the general rules of nomenclatures had priority, 

 especially as Mac. princeps Brady is naturally regarded as the type of the genus and as the name 

 Heterocalanus has been previously used for anothed genus of Calanoids. In the Report from the 

 Siboga Expedition, Scott (p. 44) established a new genus Bradycalanus with a single species B. typicus, 

 which differs from Heterocalanus by the head without crest, by the pointed lateral corners of the 

 last thoracic somite, and by the well developed Se of Re I II pes I and 2 Se Re III of pes I. He 

 writes: "I think that it is probable that Brady's Calanus princeps belongs to this genus rather than 

 to Bathycalanus or Heterocalanus"; accordingly, instead of establishing a new generic name, he ought 

 to have accepted Macrocalanus G. O. Sars. 



