REPORT ON THE DEEr-SEA MEDUSAE. iii 



the deep-sea Medusae may be regarded as the first instalment from an interesting region 

 from which we may expect many and important conclusions as to the organisation of 

 the Medusae. 



It will be seen from the systematic survey on p. 141 that altogether eight orders of 

 this class, distinguished by me in my System der Medusen, 1879, are represented 

 among the eighteen deep-sea Medusae of the Challenger expedition. Of these one species 

 (Thamnostylus, PI. I.) belongs to Order I. Anthomedusge ; one species [Ptyclwxjena, 

 PI. II.) to Order II. Leptomedusae ; three species (Pectyllis, Pedis, and Pectanthis, 

 Pis. III.— VIII.) to Order III. Trachomedusae ; four species (Cunarcha, Polycolpa, 

 Pegantha, JEgiimra, Pis. IX.-XIV.), to Order IV. Narcomedusae ; two species (Tessev- 

 antha and Lucemaria, Pis. XV.-XVII.) to Order V. Staurontedusae ; two species (Peri- 

 phylla and Periphema, Pis. XVIII.-XXV.) to Order VI. Peromedusaa ; one species 

 (CJiarybdea, PI. XXVI.) to Order VII. Cubomedusae ; four species (Nauphanta, Atolla, 

 Drymoncma, Leonura, Pis. XXVII.-XXXII.) to Order VIII. Discomedusae. Thus 

 thirteen of the thirty -two families which I defined in my System der Medusen, 1879, are 

 represented here (comp. p. 141). 



A tabular view of the chorology of these Medusae is given on p. 142. Their 

 geographical distribution extends throughout the whole of the great oceans; on the whole, 

 there are eight species in the Atlantic-Mediterranean region, and ten species in the Indo- 

 Pacific region. Of the eight former species seven belong to the northern, one to the 

 southern half of the Atlantic Ocean (two of which are also found in the Mediterranean). 

 Of the remaining ten species, two belong to the north half, three to the southern half 

 of the Pacific Ocean, and five to the Antarctic part of the Indian Ocean. One of the 

 latter is also found in the south-western part of the Atlantic. 



With regard to the bathymetrical distribution, it will be seen from the table on p. 142 

 that seven species were taken in depths from 80 to 600 fathoms, six species in depths 

 from 1100 to 1600 fathoms, and five species in depths from 2000 to 2200 fathoms. For 

 reasons already stated, these depths must (partly at least) be considered more or less 

 approximate. 



With regard to the figures of the deep-sea Medusas in the' thirty-two plates appended 

 to this Memoir, it is of course impossible, from the imperfect state of preservation of the 

 spirit specimens, to expect that they should be absolutely true to nature. I rather con- 

 sidered it my duty here, as in those figures in my System der Medusen which were 



