Leucocranchia pfefferi Joubin, 1912 Bathothauma lyromma, the lyre cranch squid, is a highly modified species of glass squid from the family Cranchiidae with a distribution which encompasses most of the world's oceans from the tropics to high latitudes.

Bathothauma lyromma is an atypical glass squid which has very large paralarva which can reach a mantle length of 100mm and has its eyes mounted on a long stalk possesses and a very long brachial pillar.

The small, paddle shaped fins are widely separated and position sub-terminally.

There is a photophore on each eye, an unusual feature in the Cranchiidae, shared only with Helicocranchia.

[3] The long eye-stalked paralarvae of Bathothauma lyromma are plantonic and are found in the upper water column from less than 100m in depth down to 300m.